We have been studying the presence of receptors for atrial natriuretic factor (ANF) and Angiotensin II (AII) in the central nervous system (CNS), and in several peripheral tissues in a high renin hypertensive rat model (2 kidney, 1 clip). We found specific ANF and AII binding on several areas of the brain that are associated with circulatory control and we are working to determine if there is any difference in this binding between control and hypertensive animals. We have found an increase in the number of ANF binding sites in several circumventricular areas and in the choroid plexus. These results are similar to our earlier findings in spontaneously hypertensive rats. In peripheral organs, we have found a difference in the number of binding sites for Angiotensin converting enzyme (ACE) in renal tubules.